"It was 5am. The whole neighbourhood was calm. People were supposed to be sleeping, that how peaceful this should be," he said.

"I was shocked to learn this happened".

Yasir Abdalrahman, a worshipper at the mosque, said the explosion was "unimaginable".

"We came to this country for the same reason everyone else came here: freedom to worship," Abdalrahman said.

"And that freedom is under threat. Every other American should be insulted by this."

Anti-Muslim crimes

The Dar Al Farooq Islamic Center serves as a religious space and community organising platform for Muslim activists and leaders in the area, according to the Muslim American Society of Minnesota.

Anti-Muslim attacks on the rise in the US

The Council on American-Islamic Relations (CAIR) urged Islamic centres and mosques across the country to step up security.

The local chapter's civil rights director, Amir Malik, said that "if a bias motive is proven, this attack would represent another in a long list of hate incidents targeting Islamic institutions nationwide in recent months".

CAIR and the mosque are offering a $10,000-reward each for information that leads to an arrest or conviction.